This invention relates to an armrest that is adjustable in a radial plane of a pivot pin associated with a back member of a seat to align the armrest in a parallel relationship with a bottom member of the seat.
Currently available automobiles often have a seat with various controls whereby the position of the seat may be adjusted to accommodate individual seating preferences. The controls may include an adjustment for an armrest and a back member. Initial armrests were designed to be moved from an in-use position that is parallel with the base or bottom of a seat to a non-use position that is parallel with the back member. Later the armrests were attached to the back member and the adjustment for the back member expanded from a substantially vertical position to a substantially horizontal position with respect to the base or bottom of the seat. Unfortunately, the alignment of the armrest mirrors the alignment changes of the back member and as a consequence when the back member is in a horizontal position, the armrest may be located at an inclined angle with respect to the base or bottom of the seat. U.S. Pat. Nos. 5,702,157, 5,984,416 and 6,663,180 disclosure various components for adjusting the armrest to provide for selective alignment with respect to the base or bottom of the seat. While the disclosed components provide for selective adjustment, the strength of the adjusting structure is limited through a single engaging pawl with a gear.
It is an object of this invention to provide an armrest retained on a back member with a mechanism to lock and retain the armrest in a desired position with respect to a base or seat bottom as the back member is rotated between a substantially vertical and a horizontal position with respect to the base or seat bottom.
The armrest has a housing that is defined by a U-shaped member with parallel first and second side walls, each of which has a first end and a second end with a first opening adjacent the second end. The housing is located on the back member by a first pivot pin that extends from the back member that and passes through the first opening in each of the first and second side walls such that the first end of the housing may pivot with respect to the first pivot pin. A first plate is fixed to the first pivot pin and is located in a first plane between the first and second side walls. The first plate has a peripheral surface with an arcuate segment removed there from to define a first stop and a second stop that correspond to a desired limit of rotation of the housing with respect to the base or seat bottom. A second plate is also fixed to the first pivot pin and located in a second plane between the first plate and the second side wall. The second plate has an arcuate surface thereon with a first plurality of teeth thereon that extend from a first location aligned with the first stop on the first plate to a second location aligned with the second stop on the first plate. A first lever has a first end that is attached to the first side wall to define a cantilevered beam and position a second plurality of teeth adjacent to a second end thereof with the first plurality of teeth on the second plate. A second lever that has a first end and a second end is located in the housing by a second pivot pin located between a first end and a second end. The second lever has an oval slot located adjacent the second end for receiving a ball such that the second pivot pin locates the ball adjacent the second plate with the ball held in tangential engagement with the second side wall and in contact engagement with the first lever. An actuator member that is attached to the first end of the second lever receives an input force that causes the second end of the second lever to pivot about the second pivot pin and move the ball along and on the second side wall such that a force is applied to the first lever through the contact engagement such that the first lever is laterally moved toward the first side wall as a function of the resiliency of the cantilevered beam. Lateral movement of the second end of the first lever moves the second plurality of teeth out of meshing engagement with the first plurality of teeth and into an alignment between the first stop and the second stop on the first plate. When the second plurality of teeth are aligned on the first plate, the first end of the housing may be moved by pivoting about the first pivot pin to a desired alignment with respect to the base or seat bottom. When the end of the housing is at a desired alignment with respect to the base or seat bottom, the input force is removed from the actuation member and the internal resiliency of the cantilevered beam returns the second end of the first lever into perpendicular alignment with the first pivot pin such that the second plurality of teeth again mesh with the first plurality of teeth to retain the first end of the housing in the desired alignment with the base or seat bottom.
An advantage of this invention resides in a robust locking mechanism for an armrest that is attached to a back member wherein a plurality of arcuate teeth are in meshing engagement with corresponding arcuate teeth on a plate fixed to a pivot pin on the back member.
It is further object of this invention is to provide an armrest that is attached to a back member the may be rotated and retained in a parallel alignment with a base or seat bottom when the back member is rotated between a vertical position and a horizontal position.